Packaging containers

ABSTRACT

This invention is concerned with a packaging container comprising an inner thin-walled hollow body of plastic material and a sleeve of a stiff, mechanically strong material open at both ends which surrounds the above hollow body.

United States Patent Inventor Gad Anders Rausing Lund, Sweden Appl. No. 808,397 Filed Mar. 19, 1969 Patented Feb. 23, 1971 Assignee Sobrefina S.A.

Fribourg, Switzerland Priority Apr. 9, 1968 Sweden 4758/68 PACKAGING CONTAINERS 1 Claim, 6 Drawing Figs.

US. Cl 220/ 220/83; 220/77 Int. Cl B65d 25/14 Field ofSearch 220/63, 75, 76,71,73, 83,65 (H), 3; 229/], 5 (B); 215]] 1, 12; 138/157; 264/94 Primary Examiner-Raphael H. Schwartz Attorney- Pierce, Scheffler & Parker ABSTRACT: This invention is concerned with a packaging container comprising an inner thin-walled hollow body of plastic material and a sleeve of a stiff, mechanically strong material open at both ends which surrounds the above hollow body.

PATENTED FEB 23 1911 3; 565280 SHEET 2 [IF 2 PACKAGING CONTAINERS There is a great need in modern distribution practice for liquidtight and mechanically strong packaging containers shaped like cans or bottles. A large number of different designs which satisfy the requirements as to liquidtightness and mechanical strength have come to be used, but they generally have the drawback that they are expensive to produce.

it is, however, possible to produce inexpensive packaging containers which satisfy the above requirements, and the packaging containers dealt with here consist of a continuous thin inner plastic lining with a cylindrical body surface and a preferably dome-shaped bottom portion. This lining can be made so thin that the body portion cannot, without support from a surrounding mechanically strong sleeve, resist the stresses caused by the liquid inside the lining, without this becoming deformed. This type of packaging container, which can also be fitted with a top portion integral with the lining, which gives the packaging container the shape of a bottle, can be produced at very low cost. Since, however, the inner lining is most conveniently produced by deep-drawing a plastic film, it has not been possible to decide the shape of the package with complete freedom, since the feasible drawing depth is restricted. 1

This invention describes a packaging-container which, in the same way as those referred to above, consists of a thin inner lining with a dome-shaped bottom portion and a mechanically stiff sleeve open at both ends which surrounds the body portion of the lining. The packaging container in accordance with the invention is however designed in such a way that the drawbacks in production due to the restricted drawing depth are avoided when the lining is produced,

One constructional version of the packaging container in accordance with the invention, ,as well as the method of producing it, will be described below, reference being made to the attached diagrammatic drawings, of which:

FIG. 1 shows a cross section of the apparatus for producing the hollow bodies for the lining;

FIG. 2 shows a different view of the apparatus;

FIG. 3 shows a plastic hollow body at the end of the production process;

FIG. 4 shows a cross section of the plastic hollow body shown in 516.3;

FlG. 5 shows the finished plastic hollow body before this is inserted into the outer sleeve;and

FIG. 6 finally shows the plastic hollow body and the outer sleeve when assembled. 1

FIG. 1 shows how a sheet 1 of the plastic material capable of being formed by heat, folded double along its centerline, is inserted after having been softened by heating between a number of interacting mould halves 2 which are capable of being pressed against the double-folded plastic sheet 1 while being moved towards one another. The mould halves 2, at least along some of the parts which are in contact with the heated sheet 1, are fitted with sealing'units 5 which heat seal to one another those parts of the sheet that are compressed between the said sealing units. The two mould halves 2 in their final position form a moulding cavity 3 which preferably has a dome-shaped bottom portion 4. The sheet 1 of thermoplastic material heated to softening temperature, which is situated between the closed mould halves 2, is caused to adhere closely to the inner surface of the moulding cavity 3 owing to the supply into the fold in the double-folded sheet 1 of a pressurized agent and/or to the moulding cavity 3 being exhausted by way of the ducts 13 which are connected to a source of vacuum. As a result of the pressure difference thus set up between the two sides of the softened sheet 1 of thermoplastic material, this will be pressed, while undergoing plastic deformation, which causes stretching of the material, against the walls of the moulding cavity, where the moulded plastic film is cooled down and stabliized. FIG. 2 shows a section through the moulding apparatus after the mould halves 2 have been moved into the closed position and the plastic film has been moulded so as to adhere to the walls of the mouldingcavity 3.

It should be observed in this connection that pro ecting fins 7 of plastic material, deformed only to a limited extent, will be formed in the area of the sealing zones. These fins 7 are stiffer than the rest of the plastic material, by virtue of the fact that they have undergone very little or no reduction in thickness, and steps are therefore taken to eliminate the drawbacks resulting from the presence of these stiff fins.

The steps which it is easiest to take are illustrated in H0. 4, where FIG. 4a shows a cross section of. a completed hollow body which has projecting fins 7. These fins 7 are folded in towards the surface of the hollow body, either while the fins are still hot and capable of plastic moulding at the end of the moulding process, or after they had again been heated to the softening temperature of the plastic material. FIG. 40 shows an enlarged detail of the fold, and it is apparent that the folded-down fin is partly pressed into the surface of the hollow body 1 with the result that no part of the fin will project outside the continuous outer surface of the hollow body. In order that the folding down of the fins should be made easier, it is best to subject the inside of the hollow body to a pressure which will counteract the inward buckling of the walls of the hollow body caused by the force required to carry out the folding down operation.

The folding down'of the fins may be carried out by heating the fins and then placing the hollow body into a cylinder whose inside surface is the same as the desired shape of the outside of the plastic hollow body. If the plastic hollow body is now rotated inside the cylinder, the fins will be forced to fold down along the surface of the hollow body and to take up the position shown in FlGS. 4band 40.

When the fins have been removed, the hollow body is inserted into an outer sleeve 8 of such length that the bottom of the hollow body 6 does not project beyond the lower edge of the sleeve 8. The plastic hollow body 6 in the constructional version shown here is provided with a projection 14, the underside of which is made to rest on theupper edge of the sleeve 8, in order that it should be possible to regulate the depth of insertion of the hollow body 6 into the sleeve 8 and to cover the upper edge of the sleeve 8.

lnorder to ensure satisfactory adhesion between the sleeve 8 and the plastic hollow body 6, these parts may be affixed to one another, e.g. by glueing.

FIG. 6 finally shows the completed packaging container which in this constructional versionhas the shape of a bottle, the top portion 11 of which has a relatively small opening 12. It is naturally possible within the framework of the idea underlying the invention to give the inner plastic hollow body another shape or to make it into an insert shaped like a can, i.e. omit the top portion 11 when moulding the plastic hollow body.

lclaim:

1. A packaging container comprising a thin-walled hollow body of plastic material, said container having a dome-shaped bottom portion, a cylindrical body portion and a conical top portion, the base of which extends outwardly beyond the circumference of the top of the cylindrical body portion to form a circumferential flange, said body portion and top portion having diametrically opposed sealedflange elements extending longitudinally along the surface of said body portion and top portion, said flange elements being folded inwardly against and pressed into said portions so as to provide substantially smooth outer surfaces thereon and a sleeve of relatively stiff material surrounding said cylindrical body portion, the lower edge of said sleeve extending downwardly at least as far as the bottom of the dome-shaped bottom portion and the upper edge of said sleeve abutting the circumferential flange formed by the conical top portion. 

1. A packaging container comprising a thin-walled hollow body of plastic mAterial, said container having a dome-shaped bottom portion, a cylindrical body portion and a conical top portion, the base of which extends outwardly beyond the circumference of the top of the cylindrical body portion to form a circumferential flange, said body portion and top portion having diametrically opposed sealed flange elements extending longitudinally along the surface of said body portion and top portion, said flange elements being folded inwardly against and pressed into said portions so as to provide substantially smooth outer surfaces thereon and a sleeve of relatively stiff material surrounding said cylindrical body portion, the lower edge of said sleeve extending downwardly at least as far as the bottom of the domeshaped bottom portion and the upper edge of said sleeve abutting the circumferential flange formed by the conical top portion. 